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At least 685 records · Page 38Linked to original sources
USGS2004

Landsat TM inventory and assessment of waterbird habitat in the southern altiplano of South America

The diverse set of wetlands in southern altiplano of South America supports a number of endemic and migratory waterbirds. These species include endangered endemic flamingos and shorebirds that nest in North America and winter in the altiplano . This research developed maps from nine Landsat Thematic Mapper (TM) images (254,300 km 2 ) to provide an inventory of aquatic waterbird habitats. Image processing software was used to produce a map with a classification of wetlands according to the habitat requirements of different types of waterbirds. A hierarchical procedure was used to, first, isolate the bodies of water within the TM image; second, execute an unsupervised classification on the subsetted image to produce 300 signatures of cover types, which were further subdivided as necessary. Third, each of the classifications was examined in the light of field data and personal experience for relevance to the determination of the various habitat types. Finally, the signatures were applied to the entire image and other adjacent images to yield a map depicting the location of the various waterbird habitats in the southern altiplano . The data sets referenced with a global positioning system receiver were used to test the classification system. Multivariate analysis of the bird communities censused at each lake by individual habitats indicated a salinity gradient, and then the depth of the water separated the birds. Multivariate analysis of the chemical and physical data from the lakes showed that the variation in lakes were significantly associated with difference in depth, transparency, latitude, elevation, and pH. The presence of gravel bottoms was also one of the qualities distinguishing a group of lakes. This information will be directly useful to the Flamingo Census Project and serve as an element for risk assessment for future development.

Wetlands Ecology and Management↗
USGS2021

Annual-cycle movements and phenology of black scoters in eastern North America

Sea ducks exhibit complex movement patterns throughout their annual cycle; most species use distinct molting and staging sites during migration and disjunct breeding and wintering sites. Although research on black scoters ( Melanitta americana ) has investigated movements and habitat selection during winter, little is known about their annual-cycle movements. We used satellite telemetry to identify individual variation in migratory routes and breeding areas for black scoters wintering along the Atlantic Coast, to assess migratory connectivity among wintering, staging, breeding, and molt sites, and to examine effects of breeding site attendance on movement patterns and phenology. Black scoters occupied wintering areas from Canadian Maritime provinces to the southeastern United States. Males used an average of 2.5 distinct winter areas compared to 1.1 areas for females, and within-winter movements averaged 1,256 km/individual. Individuals used an average of 2.1 staging sites during the 45-day pre-breeding migration period, and almost all were detected in the Gulf of St. Lawrence. Males spent less time at breeding sites and departed them earlier than females. During post-breeding migration, females took approximately 25 fewer days than males to migrate from breeding sites to molt and staging sites, and then wintering areas. Most individuals used molt sites in James and Hudson bays before migrating directly to coastal wintering sites, which took approximately 11 days and covered 1,524 km. Males tended to arrive at wintering areas 10 days earlier than females. Individuals wintering near one another did not breed closer together than expected by chance, suggesting weak spatial structuring of the Atlantic population. Females exhibited greater fidelity (4.5 km) to previously used breeding sites compared to males (60 km). A substantial number of birds bred west of Hudson Bay in the Barrenlands, suggesting this area is used more widely than believed previously. Hudson and James bays provided key habitat for black scoters that winter along the Atlantic Coast, with most individuals residing for >30% of their annual cycle in these bays. Relative to other species of sea duck along the Atlantic Coast, the Atlantic population of black scoter is more dispersed and mobile during winter but is more concentrated during migration. These results could have implications for future survey efforts designed to assess population trends of black scoters.

Chesapeake Bay, Delaware Bay, Gulf of St Lawrence,↗
USGS2021

Poecivirus is present in individuals with beak deformities in seven species of North American birds

Avian keratin disorder (AKD), a disease of unknown etiology characterized by debilitating beak overgrowth, has increasingly affected wild bird populations since the 1990s. A novel picornavirus, poecivirus, is closely correlated with disease status in Black-capped Chickadees ( Poecile atricapillus ) in Alaska. However, our knowledge of the relationship between poecivirus and beak deformities in other species and other geographic areas remains limited. The growing geographic scope and number of species affected by AKD-like beak deformities require a better understanding of the causative agent to evaluate the population-level impacts of this epizootic. Here, we tested eight individuals from six avian species with AKD-consistent deformities for the presence of poecivirus: Mew Gull ( Larus canus ), Hairy Woodpecker ( Picoides villosus ), Black-billed Magpie ( Pica hudsonia ), American Crow ( Corvus brachyrhynchos ), Red-breasted Nuthatch ( Sitta canadensis ), and Blackpoll Warbler ( Setophaga striata ). The birds were sampled in Alaska and Maine (1999−2016). We used targeted PCR followed by Sanger sequencing to test for the presence of poecivirus in each specimen and to obtain viral genome sequence from virus-positive host individuals. We detected poecivirus in all individuals tested, but not in negative controls (water and tissue samples). Furthermore, we used unbiased metagenomic sequencing to test for the presence of other pathogens in six of these specimens (Hairy Woodpecker, two American Crows, two Red-breasted Nuthatches, Blackpoll Warbler). This analysis yielded additional viral sequences from several specimens, including the complete coding region of poecivirus from one Red-breasted Nuthatch, which we confirmed via targeted PCR followed by Sanger sequencing. This study demonstrates that poecivirus is present in individuals with AKD-consistent deformities from six avian species other than Black-capped Chickadee. While further investigation will be required to explore whether there exists a causal link between this virus and AKD, this study demonstrates that poecivirus is not geographically restricted to Alaska, but rather occurs elsewhere in North America.

Alaska, Maine↗
USGS1991

Thirty-eighth supplement to the American Ornithologists' Union Check-list of North American birds

This fourth supplement after the 6th edition (1983) of the AOU "Check-list of North American Birds" consists of changes adopted by the Committee on Classification and Nomenclature between 1 March 1989 and 1 March 1991. The changes fall into eight categories: (1) five species ( Ixobrychus sinensis, Porphyrula flavirostris, Sterna bergii, Streptopelia orientalis , and Ficedula narcissina ) are added to the main list because of new distributional information; (2) six species ( Pterodroma cervicalis, Ortalis wagleri, Lophornis brachylopha, Corvus sinaloae, Cinclocerthia gutturalis , and Loxops caeruleirostris ) are added to the list because of the splitting of species previously in the list; (3) one extinct species ( Dysmorodrepanis munroi ) is added to the list because of re-identification of the unique type; (4) one scientific name ( Speotyto cunicularia ) is changed because of generic splitting; (5) one scientific name ( Phalacrocorax brasilianus ) is changed for nomenclature reasons, accompanied by a change in English name; (6) the spelling of one scientific name ( Neocrex colombianus ) is corrected; (7) to other English names are changed or corrected; and (8) one sequencing change is made. No new distributional information is included except as noted above (i.e. minor changes of distribution of distributional records within North America are not included). The twelve additions bring the number of species recognized as occurring within the Check-list area (main list) to 1957.

The Auk↗
USGS2020

At the end of the road: Lessons learned from comparing model- and design-based approaches to estimate population sizes of boreal birds in Alberta, Canada

Estimating population abundance is a challenging task complicated by the amount, type, and quality of available data. Conservationists have relied on design-based estimates from Partners in Flight (PIF), which primarily uses roadside data from the North American Breeding Bird Survey (BBS) to estimate populations sizes. However, the BBS was not designed to estimate population sizes. We developed models incorporating land cover and climate variables based on roadside and off-road point-count surveys. We calculated spatially explicit, model-based population estimates for 81 landbird species in Bird Conservation Region 6 in Alberta, Canada, and compared these to PIF estimates. We also developed a framework to evaluate how the differences between the detection distance, time-of-day, roadside count, and habitat representation adjustments explain discrepancies between the two estimators. We showed that the key assumptions of the PIF population size estimator were commonly violated in this region, and the two approaches provided very different population size estimates for most species. The average differences between estimators were explained by differences in the detection distance and time-of-day components, but these adjustments left much unexplained variation among species. Differences in the roadside count and habitat representation components explained most of the among-species variation. The variation caused by these factors was large enough to change the population size ranking of the species. The roadside count bias needs serious attention when roadside surveys are used to extrapolate over off-road areas. Habitat representation bias is likely prevalent in regions sparsely and non-representatively sampled by roadside surveys, such as the boreal region of North America, and thus population size estimates for these regions need to be treated with caution for certain species. Model-based integration of available data sources and additional sampling can contribute towards more accurate population size estimates for conservation in remote areas of North America.

Alberta↗
USGS2019

Resource selection and wintering phenology of White-winged Scoters in southern New England: Implications for offshore wind energy development

Southern New England provides key wintering habitat for White-winged Scoters ( Melanitta fusca ). This area has also pioneered the development of offshore wind energy in North America and the U.S. Bureau of Ocean Energy Management (BOEM) has established nine Wind Energy Area (WEA) lease blocks along the Atlantic Outer Continental Shelf in areas that may provide important staging and wintering habitat for scoters and other species of sea ducks. Concern over the potential impact of offshore wind energy on sea duck populations has led to efforts to develop models to understand their distribution, habitat use and site fidelity. We used satellite telemetry to document winter phenology and site fidelity, as well as fine-scale resource selection and habitat use of 40 White-winged Scoters along the southern New England continental shelf. Scoters spent over half of the annual cycle on the wintering grounds and demonstrated a high degree of inter-annual site fidelity to composite core-use areas. Sizes of individual 50% core-use home ranges were variable (x̅ = 868 km2; range = 32 to 4,220 km2) and individual 95% utilization distributions ranged widely (x̅ = 4,388 km2; range = 272 to 18,235 km2). More than half of all tagged birds occupied two or more discrete core-use areas that were up to 400 km apart. Throughout the study area, scoters selected for areas with lower salinity, lower sea surface temperature, higher chlorophyll-a concentrations, and higher hard-bottom substrate probability. Resource selection function models classified 18,649 km2 (23%) of the study area as high probability of use, which included or immediately bordered ~420 km2 of proposed WEA lease blocks. Future offshore wind energy developments in the region should avoid key habitats highlighted by this study and carefully consider the environmental characteristics selected by sea ducks when planning and siting future WEAs.

Southern New England↗
USGS2017

The Snowmastodon Project

Studies of terrestrial biotic and environmental dynamics of the last interglacial period, Marine Oxygen Isotope Stage (MIS) 5, provide insight into the effects of long-term climate change on Pleistocene ecosystems. In North America, however, there are relatively few fossil sites that definitively date to MIS 5. Even fewer contain multiple ecosystem components (vertebrates, invertebrates, plants) that have been studied in detail, and none are located at high elevation. Thus, our view of North American ecosystems during MIS 5 is, at best, an incomplete composite view, and alpine ecosystems are entirely undocumented. The Ziegler Reservoir fossil site allows us to begin filling these gaps. Discovered on October 14, 2010 by a construction crew while enlarging a small reservoir near Snowmass Village, Colorado (USA), the site is situated high in the Rocky Mountains at an elevation of ~ 2705 m. Initial excavations exposed a series of stacked fossil ecosystems, including abundant faunal and floral components. Subsequent work revealed an exceptionally diverse biota composed of nearly 6000 large bones of late Pleistocene megafauna, including mastodons, mammoths, ground sloths, horses, camels, deer, bison, black bear, coyotes, and big horn sheep. This collection is complemented by more than 200 bones from at least 40 species of small animals including otters, muskrats, minks, rabbits, beavers, frogs, lizards, snakes, fish, and birds, and more than 20,000 salamander bones. Geomorphic evidence and multiple dating techniques show that the small, ridge-top basin containing the site was formed by a lateral lobe of a valley glacier that filled, and ultimately overtopped, the Snowmass Creek drainage during the Bull Lake glaciation (MIS 6). When the glacier receded, a lake that occupied the basin began to fill slowly with what is hypothesized to be eolian sediment and occasional input from slope failures of the impounding moraine. As sedimentation continued, the lake transformed first into a shallow pond, then a marsh, and later an alpine meadow. In all, the Ziegler Reservoir sedimentary record spans the time encompassed by the end of MIS 6, all of MIS 5 and MIS 4, and the earliest part of MIS 3. MIS 5e, which is considered to be the peak warmth of the last interglacial period, is especially well represented. Preservation of organic material at the Ziegler Reservoir fossil site is exceptional. Even after more than 100,000 years of burial, sedge and willow leaves were still green, mollusks and gastropods showed color, beetle parts remained iridescent, fossil conifer cones were intact, and an entire beach of 20-meter-long driftwood logs was found intact. The exquisite preservation allowed for detailed analysis of pollen, plant macrofossils, conifer cones, and fossil wood, as well as insects, chironomids, mollusks, ostracodes, and other invertebrates — all in addition to the spectacular faunal remains. This special volume of Quaternary Research represents a comprehensive scientific report of “The Snowmastodon Project,” as the investigations at the Ziegler Reservoir fossil site came to be known. Summarizing the work of scientists from more than 20 institutions, the volume details the environments in which the animals lived, provides insight into how they died, and forms the foundation of our understanding of alpine ecosystem dynamics during the last interglacial period in the Rocky Mountains.

Quaternary Research↗
USGS2024

Abundance of Long-billed Curlews on military lands in the Columbia Basin

Long-billed Curlews ( Numenius americanus ) are declining throughout North America, and the loss of grassland breeding habitat is one of the primary threats to the species. Intermountain West, in particular, has been identified as the most important region in North America for breeding curlews. Nevertheless, the density and abundance of Long-billed Curlews in this region is not well understood. Lands managed for military training can provide habitat for wildlife species of conservation concern, and increasingly these lands are becoming relevant to sustaining biodiversity. We conducted point count surveys of Long-billed Curlews on Department of Defense lands in the Columbia Basin near Boardman, Oregon, USA during two consecutive breeding seasons. We used multinomial-Poisson mixture models to estimate detection probability and density of curlews and to investigate environmental correlates of those metrics. Mean detection probability at a distance of 400 m was 0.45 and 0.61 in 2015 and 2016, respectively. In 2015, the clarity of skies increased detection probability, but in 2016, none of the variables we measured influenced detection probability. Mean predicted density was 3.3 (95% confidence interval: 2.4–4.7) and 1.8 (1.2–2.7) curlews/km² in 2015 and 2016, respectively. In both years, curlew density was higher in lower-elevation or topographically smoother areas. Estimated abundance of curlews in the study area was 639 (456–912) and 350 (237–520) birds in 2015 and 2016, respectively. The number of curlews appeared to fluctuate across the two years of our study, a demographic trend that may have been influenced by a wildfire in our study area in June 2015. The results of our study indicate that federal grasslands, including areas where military operations are conducted, can provide conservation benefit to breeding Long-billed Curlews.

Oregon↗
USGS1983

Organochlorine residues and shell characteristics of roseate tern eggs, 1981

Roseate Terns ( Sterna dougallii ) breed in two areas in the Western Hemisphere: in northeastern North America between Long Island, New York, and Nova Scotia, and around the Caribbean Sea from the Florida Keys and the Bahamas to the Netherlands Lesser Antilles (Bent 1921, Bond 1956, Nisbet 1980). Both populations are small, and concern recently has been expressed about their status (Nisbet 1980, Buckley and Buckley 1981). The northeastern population has decreased from a peak of about 8500 pairs in the 1940s to between 2500 and 3000 pairs in 1978-1982, and has become largely concentrated into 4 colonies (Nisbet 1980). The Caribbean population has been affected by egg collecting and other forms of human disturbance in its main stronghold in the U.S. Virgin Islands (U.S. Virgin Islands Bureau of Fish and Wildlife 1976-1979, Norton 1980, 1981). One factor which may have affected the northeastern population is chemical pollution. Hays and Risebrough (1972) reported high levels of polychlorinated biphenyls (PCBs) and l,l-dichloro-2,2-bis(p-chloro phenyl) ethylene (DDE) in 3 Roseate Tern chicks found with congenital abnormalities at Great Gull Island, New York, in 1970. High levels of PCBs were also found in chicks found dead at Bird Island, Massachusetts, in 1970 (Nisbet 1981). A close relative, the Common Tern ( S. hirundo ), is relatively sensitive to the effects of DDE; elevated residues of DDE in eggs are associated with eggshell-thinning (Switzer et al. 1973), reduction in the porosity of eggshells, and embryonic mortality (Fox 1976). The present paper reports the results of a survey of organochlorine residues in Roseate Terns in 1981. The main objectives of the survey were to determine the levels of organochlorine contamination in eggs of the Roseate Tern in its major colonies and to investigate whether changes in eggshell characteristics similar to those reported by Fox (1976) may have occurred in this species. A secondary objective was to determine geographic patterns of organochlorine contamination within the northeastern U.S. population of Roseate Terns and to compare them with patterns observed in Common Terns

Connecticut, Massachusetts, New York↗
USGS2005

Long-range movements and breeding dispersal of Prairie Falcons from southwest Idaho

From 1999–2003, we tracked movements of adult female Prairie Falcons ( Falco mexicanus ) using satellite telemetry to characterize long-range movement patterns and breeding dispersal. We radio marked 40 falcons from April–May on their nesting grounds in the Snake River Birds of Prey National Conservation Area in southwest Idaho. All falcons with functioning transmitters left the Snake River Canyon from late June through mid-July. Most headed northeast across the Continental Divide to summering areas in Montana, Alberta, Saskatchewan, and the Dakotas. Prairie Falcons stayed at their northern summer areas for 1–4 months before heading to the southern Great Plains or to southwest Idaho. The Great Plains was a key migration pathway. Important wintering areas included the Texas Panhandle and southwest Idaho. Most falcons completed their seasonal migrations within 2 weeks. Use of widely separated nesting, summering, and wintering areas appears to be a strategy to exploit seasonally abundant prey resources. Most falcons had three or fewer use areas during the nonbreeding season, and falcons showed a high degree of fidelity to their use areas during each season. At least 21 falcons returned to nest within 2.5 km of where they nested in the previous year, but one falcon moved to a new nesting area 124 km south of her previous breeding area. Prairie Falcon movements suggest large-scale connectivity of grassland and shrubsteppe landscapes throughout western North America. Conservation of Prairie Falcons must be an international effort that considers habitats used during both nesting and non-nesting seasons.

Idaho↗
USGS2019

Spatial integration of biological and social objectives to identify priority landscapes for waterfowl habitat conservation

Waterfowl population management and habitat conservation compose one of the oldest and most successful adaptive management frameworks in the world. Since its inception, the North American Waterfowl Management Plan (NAWMP) has emphasized strategically targeted conservation investments in regions that most affect waterfowl population dynamics. By 2012, regional conservation had progressively become more science-based and strategic: many migratory bird partnerships had initiated or completed projects on mapping and modeling waterfowl distribution and abundances using geospatial techniques. However, when developing a map depicting and titled “Areas of Greatest Continental Significance to North American Ducks, Geese, and Swans” for the 2012 NAWMP Revision, waterfowl professionals articulated the need for improved decision frameworks and use of consistent datasets for refining large-scale spatial products depicting priority areas for waterfowl and people. This report describes a framework for developing a spatial value model to support the identification of North American geographies of importance to waterfowl during the breeding and non-breeding periods and to resource users who could potentially support (financially and (or) politically) waterfowl habitat conservation. Objectives used to identify priority geographies were determined through a collaborative process of the NAWMP Science Support Team, Priority Landscapes Committee (PLC), and other experts in the fields of waterfowl biology and ecology, environmental science, and human dimensions. ArcGIS Desktop was used as the platform for managing, analyzing, combining and displaying the spatial data as well as producing new data through spatial analysis functions. Thirty-eight spatial layers were developed, and several composite spatially explicit products (maps of North America) were produced based on PLC recommendations. The composite products have extensive similarities to the 2012 NAWMP map depicting areas of greatest continental significance to North American waterfowl. There are also some differences, especially in regions of the high Arctic and in Mexico. These differences between spatial value model maps and the 2012 NAWMP output likely arose from inclusion of social objectives, reduced dependence on expert opinion to generate abundance estimates, lack of population surveys in some regions and availability of expanded survey data in other regions, and use of model-based waterfowl population estimates for some unsurveyed areas. The structured decision-making framework application in this study is discussed, and the appropriate use of the products and their limitations are outlined. Additionally, options for future improvements are presented by identifying gaps in data collection, waterfowl-habitat association assumptions, and uncertainties related to social objectives. These spatial products are intended for use by national, regional, and province/state level wildlife professionals to aid their decisions in targeting waterfowl habitat conservation.

Open-File Report↗
USGS2025

Interacting sea-level rise, sea-ice loss, storm flooding, erosion, and permafrost thaw threaten ecosystems, wildlife, and communities on the Yukon-Kuskokwim Delta

The Yukon-Kuskokwim Delta has the largest intertidal wetland in North America, is a globally critical breeding area for waterbirds, and is home to the largest regional indigenous population in the Arctic. Here, coastal tundra ecosystems, wildlife, and indigenous communities are highly vulnerable to sea-ice loss in the Bering Sea, sea-level rise, storm flooding, erosion, and collapsing ground from permafrost thaw caused by climate warming. These drivers interact in non-linear ways to increase flooding, salinization, and sedimentation, and thus, alter ecosystem trajectories and broader landscape evolution. Rapid changes in these factors over decadal time scales are highly likely to cause transformative shifts in coastal ecosystems across roughly 70% of the outer delta this century. We project saline and brackish ecotypes on the active delta floodplain with frequent sedimentation will maintain dynamic equilibrium with sea-level rise and flooding, slightly brackish ecotypes on the inactive floodplain with infrequent flooding and low sedimentation rates will be vulnerable to increased flooding and likely transition to more saline and brackish ecotypes, and fresh lacustrine and lowland ecotypes on the abandoned floodplain with permafrost plateaus will be vulnerable to thermokarst, salinization and flooding that will shift them toward brackish ecosystems. This will greatly affect bird nesting and foraging habitats, with both winners and losers. Already, some Yup'ik communities are facing relocation of their low-lying villages. The societal challenges and consequences of adapting to these changing landscapes are enormous and will require a huge societal effort.

Alaska↗
USGS2026

Rain interacts with directional wind to cause nest failures within breeding colonies of Western and Clark's Grebes

Western Grebe ( Aechmophorus occidentalis ) and Clark's Grebe ( Aechmophorus clarkii ) populations have declined across their range, and they are species of high conservation concern. Cascade Reservoir in central Idaho supports one of the largest breeding colonies of Aechmophorus grebes in North America (and the largest in Idaho), but few offspring are produced from the colony in most years. Low fecundity and little natal recruitment may be the proximate cause of Aechmophorus grebe population declines, but the ultimate cause of low recruitment is not known. One hypothesis for the low fecundity at Cascade Reservoir (and at other grebe colonies in the region) is that waves on freshwater breeding lakes inundate nests and cause pairs to abandon their nests. We tested that hypothesis by examining whether nest survival was negatively associated with changes in daily water level, daily peak wind speed and daily peak wind direction (i.e. winds that push water into the breeding colony). We also included daily mean temperature and daily total precipitation to evaluate a more general hypothesis that weather events caused nest failures. We used aerial imagery obtained from repeated drone flights to create encounter histories for 3888 Aechmophorus grebe nests to then estimate daily nest survival and evaluate whether daily water level, daily peak wind speed and daily peak wind direction (as predicted by the wind-driven wave hypothesis) were important causes of nest failure relative to other factors that commonly affect daily nest survival in birds. Nesting success was alarmingly low and we found some support for the wave inundation hypothesis; the results suggest that nesting attempts are more likely to fail on days with precipitation combined with winds blowing into the colony. Our results are the first to show that wind and precipitation affect the nest fate of Aechmophorus grebes.

Idaho↗
USGS2024

Identifying an understudied interface: Preliminary evaluation of the use of retention ponds on commercial poultry farms by wild waterfowl

While the recent incursion of highly pathogenic avian influenza into North America has resulted in notable losses to the commercial poultry industry, the mechanism by which virus enters commercial poultry houses is still not understood. One theorized mechanism is that waterfowl shed virus into the environment surrounding poultry farms, such as into retention ponds, and is then transmitted into poultry houses via bridge species. Little is known about if and when wild waterfowl use these retention ponds, leading to uncertainty regarding the potential significance of this interface. To quantify the use of retention ponds on commercial poultry farms by wild waterfowl, we surveyed 12 such ponds across Somerset and Dorchester counties, Maryland, USA. This region was chosen due to the high level of poultry production and its importance for migratory waterfowl. Surveys consisted of recording waterfowl visible on the retention ponds from public roadways at least once per week from 20 September 2022–31 March 2023. Throughout the course of this study, we observed a total of nine species of waterfowl using retention ponds on commercial poultry farms at nine of 12 sites. The number of waterfowl observed at retention ponds varied notably throughout the course of our survey period, with values generally following trends of fall migration within each species indicating that resident birds were not the only individuals to utilize these habitats. Additionally, waterfowl use was highest at sites with little vegetation immediately surrounding the pond, and lowest when ponds were surrounded by trees. Our data suggest that retention ponds on commercial poultry farms present a notable interface for waterfowl to introduce avian influenza viruses to farm sites. However, additional testing and surveys could provide further insight into whether it may be possible to reduce the use of these habitats by wild waterfowl through vegetative management as preliminarily reported here.

Transboundary and Emerging Diseases↗
USGS2005

Edge and area effects on the occurrence of migrant forest songbirds

Concerns about forest fragmentation and its conservation implications have motivated numerous studies that investigate the influence of forest patch area and forest edge on songbird distribution patterns. The generalized effects of forest patch size and forest edge on animal distributions is still debatable because forest patch size and forest edge are often confounded and because of an incomplete synthesis of available data. To fill a portion of this gap, we incorporated all available published data (33 papers) in meta-analyses of forest edge and area effects on site occupancy patterns for 26 Neotropical migrant forest-nesting songbirds in eastern North America. All reported area effects are confounded or potentially confounded by edge effects, and we refer to these as "confounded" studies. The converse, however, is not true and most reported edge effects are independent of patch area. When considering only nonconfounded studies of edge effects, only 1 of 17 species showed significant edge avoidance and 3 had significant affinity for edges. In confounded studies, 12 of 22 species showed significant avoidance of small patches and edges, and 1 had an affinity for small patches and edges. Furthermore, average effect sizes averaged across studies or species tended to be higher for confounded studies than for edge studies. We discuss three possible reasons for differences in results between these two groups of studies. First, studies of edge effects tended to be carried out in landscapes with greater forest cover than studies of confounded effects; among confounded effects studies, as forest cover increased, we observed a nonsignificant trend towards decreasing strength of small patch or edge avoidance effects. Thus, the weaker effects in edge studies may be due to the fact that these studies were conducted in forest-dominated landscapes. Second, we may have detected strong effects only in confounded studies because area effects are much stronger than edge effects on bird occurrence, and area effects drive the results in confounded studies. Third, edge and area effects may interact in such a way that edge effects become more important as forest patch size decreases; thus, both edge and area effects are responsible for results in confounded studies. These three explanations cannot be adequately separated with existing data. Regardless, it is clear that fragmentation of forests into small patches is detrimental to many migrant songbird species. ??2005 Society for Conservation Biology.

Conservation Biology↗
USGS2015

Genetic diversity and host specificity varies across three genera of blood parasites in ducks of the Pacific Americas Flyway

Birds of the order Anseriformes, commonly referred to as waterfowl, are frequently infected by Haemosporidia of the genera Haemoproteus , Plasmodium , and Leucocytozoon via dipteran vectors. We analyzed nucleotide sequences of the Cytochrome b (Cyt b ) gene from parasites of these genera detected in six species of ducks from Alaska and California, USA to characterize the genetic diversity of Haemosporidia infecting waterfowl at two ends of the Pacific Americas Flyway. In addition, parasite Cyt b sequences were compared to those available on a public database to investigate specificity of genetic lineages to hosts of the order Anseriformes. Haplotype and nucleotide diversity of Haemoproteus Cyt b sequences was lower than was detected for Plasmodium and Leucocytozoon parasites. Although waterfowl are presumed to be infected by only a single species of Leucocytozoon , L . simondi , diversity indices were highest for haplotypes from this genus and sequences formed five distinct clades separated by genetic distances of 4.9%–7.6%, suggesting potential cryptic speciation. All Haemoproteus and Leucocytozoon haplotypes derived from waterfowl samples formed monophyletic clades in phylogenetic analyses and were unique to the order Anseriformes with few exceptions. In contrast, waterfowl-origin Plasmodium haplotypes were identical or closely related to lineages found in other avian orders. Our results suggest a more generalist strategy for Plasmodium parasites infecting North American waterfowl as compared to those of the genera Haemoproteus and Leucocytozoon .

PLoS ONE↗
USGS2014

Estimates of annual survival, growth, and recruitment of a white-tailed ptarmigan population in Colorado over 43 years

Long-term datasets for high-elevation species are rare, and considerable uncertainty exists in understanding how high-elevation populations have responded to recent climate warming. We present estimates of demographic vital rates from a 43-year population study of white-tailed ptarmigan ( Lagopus leucura ), a species endemic to alpine habitats in western North America. We used capture-recapture models to estimate annual rates of apparent survival, population growth, and recruitment for breeding-age ptarmigan, and we fit winter weather covariates to models in an attempt to explain annual variation. There were no trends in survival over the study period but there was strong support for age and sex effects. The average rate of annual growth suggests a relatively stable breeding-age population ( λ ¯ "> λ ¯ = 1.036), but there was considerable variation between years for both population growth and recruitment rates. Winter weather covariates only explained a small amount of variation in female survival and were not an important predictor of male survival. Cumulative winter precipitation was found to have a quadratic effect on female survival, with survival being highest during years of average precipitation. Cumulative winter precipitation was positively correlated with population growth and recruitment rates, although this covariate only explained a small amount of annual variation in these rates and there was considerable uncertainty among the models tested. Our results provide evidence for an alpine-endemic population that has not experienced extirpation or drastic declines. However, more information is needed to understand risks and vulnerabilities of warming effects on juveniles as our analysis was confined to determination of vital rates for breeding-age birds.

Colorado↗
USGS1990

Sago pondweed (Potamogeton pectinatus L.): A literature review

Sago pondweed ( Potamogeton pectinatus L.) is a submersed macrophyte of nearly cosmopolitan distribution. The plant is of worldwide importance as a waterfowl food but also can be a nuisance in irrigation canals and recreational areas. The plant reproduces by many different means, depending on habitat and environmental stress. Several genetic ecotypes have evolved. Most important as waterfowl food are the turions (tubers), vegetative propagules rich in carbohydrates that are mostly buried in bottom sediments. In temperate wetlands, most turions sprout in spring, making sago behave as an annual. Drupelets (seeds) are the sexual propagules of sago and provide a mechanism for sago to survive periods of drought and excessive water salinity. Drupelets can be washed ashore or carried by birds for long distances. Sago decomposes rapidly at senescence, annually in temperate wetlands. Sago is mostly found in semipermanently or permanently flooded mixosaline lacustrine, palustrine, and riverine wetlands < 2.5 m deep, where fetches are not large or currents are < 1 m/s. Sago seems to prefer stable water levels but can tolerate significant water level fluctuations. Among the Potamogetons, only sago tolerates high salinity, pH, and alkalinity, but it fares poorly among specialist taxa in acidic or nutrient-poor waters. Sago is highly tolerant of eutrophic waters, and it can be the only species of submersed macrophyte present in heavily polluted sites. Sago grows in nearly all bottom substrates. Turbidity is the factor that most frequently limits sago growth. Sago often occurs in monotypic stands but can grow with many other submersed and emergent macrophytes. Dominance by sago in certain wetlands sometimes alternates with dominance by other submersed macrophytes when salinities or other environmental factors change. Sago also can be associated with a large variety of unattached filamentous, planktonic, or epiphytic algae. Increased turbidity caused by planktonic algae often is responsible for lowered sago production. Less common biotic limiting factors are organic pollutants and consumption and uprooting by waterfowl and fish. Sago provides food or shelter for amphibians, reptiles, fish, and mammals. The greatest value of sago in North America is as food for migrant and staging waterfowl, primarily diving ducks and swans. Sago beds also provide habitat for a large complex of invertebrates (an important food source for young waterfowl), but direct consumption of living sago by invertebrates is negligible. Sago has been propagated for many years-indoors, as an experimental organism for work in plant physiology or herbicide testing, and outdoors, for purposes of attracting waterfowl. Much work has also been done developing methods to control excessive sago growth in fishponds and irrigation canals. Future research should concentrate on (1) determining, in a variety of wetland types, the causes of light-limiting turbidity that often suppresses sago growth, (2) understanding the ways in which human activities on and near wetlands affect sago production, and (3) developing reliable and predictable techniques to stimulate sago production for waterfowl by using water level manipulations and other means, in a variety of environmental settings.

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